Life expectancy

Life expectancy is the most likely number of years remaining for a living being (or the average for a class of living beings) of a given age to live.

Life expectancy over human history

Life expectancy has dramatically increased over the last few centuries of human history. These changes are largely the result of improvements in public health, medicine, and nutrition. The greatest improvements have been made in the richest parts of the world, but the same effects are now spreading to other parts of the world as their economies and infrastructure improve.

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Life expectancy increased dramatically in the 20th century, especially in developed nations. Life expectancy at birth in the United States in 1901 was 49 years. At the end of the century it was 77 years, an increase of greater than 50%. Similar gains have been enjoyed throughout the world. Life expectancy in India and The People's Republic of China was around 40 years at midcentury. At century's close it had risen to around 63 years. These gains were due largely to the eradication and control of numerous infectious diseases and to advances in agricultural technology (such as chemical fertilizers).

Related Topics:
20th century - United States - India - People's Republic of China - Chemical fertilizers

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Basic life expectancy numbers tend to exaggerate this growth, however. The low level of pre-modern life expectancy is distorted by the previous extremely high infant and childhood mortality. If a person did make it to the age of forty they had an average of another twenty years to live. Improvements in medicine, public health, and nutrition have therefore mainly increased the numbers of people living beyond childhood, with less effect on overall average lifespan.

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These improvements continue to confound the predictions of Thomas Malthus, who predicted what is now known as the Malthusian catastrophe which would occur when population growth exceeded the capacity of the world to sustain that population.

Related Topics:
Thomas Malthus - Malthusian catastrophe

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The major exception to this general pattern of improvement has been in those countries worst hit by AIDS, principally in Sub-Saharan Africa, which have seen significant falls in life expectancy due to the disease in recent years. European socialist countries (such as the Soviet Union, Poland, Czechoslovakia and Hungary) were characterized by decreasing life expectancy and increasing mortality (especially among adult men) in the late 1960s, 1970s and 1980s. Another exception is Russia and other former USSR republics after the collapse of the Soviet Union. Life expectancy of men dropped to 59.9 years (below the official retirement age), of women to 72.43 years (1999).

Related Topics:
AIDS - Soviet Union - Poland - Czechoslovakia - Hungary - 1960s - 1970s - 1980s - Russia - Collapse of the Soviet Union - Retirement

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In recent years, obesity-correlated diseases have become a major public health issue in many countries. The prevalence of obesity is thought to have reduced a potential for longer life expectancy by contributing to the rise of cancers, heart disease and diabetes in the developed world.

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Throughout human history most of the increase in life expectancy arose from preventing early deaths. However, many scientists believe this will not stay true in the future as medical advancements aimed at halting or even reverting aspects of the aging process become widely available.

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